ChemInform Abstract: INFLUENCE OF STERIC EFFECTS ON THE SELECTIVITY OF RADICAL CARBON‐CARBON BONDING

Abstract

Die acyclischen Radikale (III), die durch Mercurierung der entsprechenden Hydrazone und nachfolgende Reduktion erzeugt werden, lassen sich durch (II) bzw. (IV) abfangen, wobei Verhältnisse der Geschwindigkeitskonstanten erhalten werden, die mit zunehmender Raumerfüllung von R′ von 1.9 auf 0.09 abnehmen.

Molecular Surface Functionalization of Carbon Materials via Radical-Induced Grafting of Terminal Alkenes

“…A similar behavior has been noted in the reaction of more typical organic reactions of radicals with alkenes. While in liquid-phase reactants branched products (formed by C–C bond formation at C2) are lower in energy than bonding at C1, prior studies of radical reactions with alkenes have found a strong preference for linking to the terminal C1 due to the smaller steric constraints there. , Similarly, we find that binding via the C2 position is strongly disfavored on both (111) and (100) diamond surfaces. Taken together from both experimental and computational results, our data demonstrate that radicals first form on the diamond surfaces and then regioselectively bind with the alkene terminus via covalent linkage to form a monolayer.…”

“…The citric acid-derived polymeric carbon dots (CAPCDs) were synthesized using a previously reported procedure in which citric acid is mixed with a polyamine and exposed to intense microwave excitation, leading to an extensive polymerization and the formation of small luminescent carbon nanoparticles. , Full characterization data for our CAPCDS are contained in ref . The CAPCDs were used in their as-synthesized condition due to the presence of accessible C–H bonds at their surfaces (vide infra).…”

“…NMR and DFT calculations further show that the alkenes link to the diamond surface regioselectively at the terminal C atom, in an anti-Markovnikov configuration, due to severe hindrance that would result from linking at the second C atom. A similar trend has been noted in organic reactions of radicals with terminal alkenes, and similarly attributed primarily to steric effects . Our results show that that surface-selective H atom abstraction offers a stable, scalable, selective, and flexible approach for functionalization of carbon-based materials with molecules via an all-carbon scaffold.…”

“…A similar trend has been noted in organic reactions of radicals with terminal alkenes, and similarly attributed primarily to steric effects. 42 Our results show that that surface-selective H atom abstraction offers a stable, scalable, selective, and flexible approach for functionalization of carbon-based materials with molecules via an all-carbon scaffold.…”